Is this some type of exercise for tai chi..what is it called?

what is it called when you have one leg on something, then the other leg somewhere else. Let's say I had two stacked mattress beds on the right of me and the left of me...I'm in between the mattress then I put one of my feet on one mattress and the other foot on the other one while standing up. I seen this guy doing it on a movie named ong bak...he was on a tree...what is it called?